Traditional wireless networks include a number of base stations (BTS) and one or more mobile switching centers (MSC)/base station controllers (BSC). The BTSs each cover a geographic region, or cell of the wireless network and communicate with mobile telephones in the cell. The MSCs/BSCs provide switch and soft handoff functionality for the wireless network. To support data calls, wireless networks typically include a data interworking function (IWF). The IWF connects the wireless network to the Internet or other data network.
Each cell of a wireless network is able to support a certain number or bandwidth of wireless calls. This capacity is a function of the maximum transmit power, frequency reuse, carrier to interference ratio, bit energy-to-noise ratio, effective bit-rate protocol and other criteria of the wireless link. To prevent the maximum power from being exceeded for a cell and thus damaging the transmitter, call and handoff admissions are blocked when the transmit power level exceeds established thresholds. Typically, the call blocking threshold is lower than the handoff blocking threshold to provide priority to existing calls entering the cell.
In operation, admission requests are processed as they are received. New call originations are blocked when the transmit power at the cell exceeds the call blocking threshold while handoff requests are still serviced normally. When the transmit power exceeds the higher handoff blocking threshold, both call origination and handoff requests are denied service.